Commitments and Contingencies, Environmental (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Jun. 30, 2016
Environmental Contingency
Environmental accrual	$ 17.5	$ 17.5
Expected period related to remediation expenditures for environmental contingencies period		30 years
Potential increase in environmental costs	$ 12.3	$ 12.3	$ 24.7
Time period within which Companys recorded estimate of its obligation may change	12 months
Maximum
Environmental Contingency
Period for final feasibility study		12 months